source: trunk/python/asapmath.py @ 981

from scantable import scantable
from asap import rcParams
from asap import print_log

def average_time(*args, **kwargs):
    """
    Return the (time) average of a scan or list of scans. [in channels only]
    The cursor of the output scan is set to 0
    Parameters:
        one scan or comma separated  scans
        mask:     an optional mask (only used for 'var' and 'tsys' weighting)
        scanav:   True averages each scan separately.
                  False (default) averages all scans together,
        weight:   Weighting scheme. 'none, 'var' (1/var(spec)
                  weighted), 'tsys' (1/Tsys**2 weighted), 'tint'
                  (integration time weighted) or 'tintsys' (Tsys
                  and tint). The default is 'tint'
        align:    align the spectra in velocity before averaging. It takes
                  the time of the first spectrum in the first scantable
                  as reference time.
    Example:
        # return a time averaged scan from scana and scanb
        # without using a mask
        scanav = average_time(scana,scanb)
        # return the (time) averaged scan, i.e. the average of
        # all correlator cycles
        scanav = average_time(scan, scanav=True)
    """
    scanav = False
    if kwargs.has_key('scanav'):
       scanav = kwargs.get('scanav')
    weight = 'tint'
    if kwargs.has_key('weight'):
       weight = kwargs.get('weight')
    mask = ()
    if kwargs.has_key('mask'):
        mask = kwargs.get('mask')
    align = False
    if kwargs.has_key('align'):
        align = kwargs.get('align')
    varlist = vars()
    if isinstance(args[0],list):
        lst = args[0]
    elif isinstance(args[0],tuple):
        lst = list(args[0])
    else:
        lst = list(args)

    del varlist["kwargs"]
    varlist["args"] = "%d scantables" % len(lst)
    # need special formatting here for history...

    from asap._asap import stmath
    stm = stmath()
    for s in lst:
        if not isinstance(s,scantable):
            msg = "Please give a list of scantables"
            if rcParams['verbose']:
                print msg
                return
            else:
                raise TypeError(msg)
    if scanav: scanav = "SCAN"
    else: scanav = "NONE"
    alignedlst = []
    if align:
        refepoch = lst[0].get_time(0)
        for scan in lst:
            alignedlst.append(scan.freq_align(refepoch,insitu=False))
    else:
        aligendlst = lst
    s = scantable(stm._average(alignedlst, mask, weight, scanav))
    s._add_history("average_time",varlist)
    print_log()
    return s

# def quotient(source, reference, preserve=True):
#     """
#     Return the quotient of a 'source' (signal) scan and a 'reference' scan.
#     The reference can have just one row, even if the signal has many. Otherwise
#     they must have the same number of rows.
#     The cursor of the output scan is set to 0
#     Parameters:
#         source:        the 'on' scan
#         reference:     the 'off' scan
#         preserve:      you can preserve (default) the continuum or
#                        remove it.  The equations used are
#                        preserve:  Output = Toff * (on/off) - Toff
#                        remove:    Output = Toff * (on/off) - Ton
#     """
#     varlist = vars()
#     from asap._asap import quotient as _quot
#     s = scantable(_quot(source, reference, preserve))
#     s._add_history("quotient",varlist)
#     print_log()
#     return s

def simple_math(left, right, op='add', tsys=True):
    """
    Apply simple mathematical binary operations to two
    scan tables,  returning the result in a new scan table.
    The operation is applied to both the correlations and the TSys data
    The cursor of the output scan is set to 0
    Parameters:
        left:          the 'left' scan
        right:         the 'right' scan
        op:            the operation: 'add' (default), 'sub', 'mul', 'div'
        tsys:          if True (default) then apply the operation to Tsys
                       as well as the data
    """
    varlist = vars()
    print "Not yet available in asap"
    return
    if not isinstance(left,scantable) and not isinstance(right,scantable):
        msg = "Please provide two scantables as input"
        if rcParams['verbose']:
            print msg
            return
        else:
            raise TypeError(msg)
    s = scantable(stm._bop(left, right, op, tsys))
    s._add_history("simple_math", varlist)
    print_log()
    return s

def merge(*args):
    """
    """
    varlist = vars()
    if isinstance(args[0],list):
        lst = tuple(args[0])
    elif isinstance(args[0],tuple):
        lst = args[0]
    else:
        lst = tuple(args)
    varlist["args"] = "%d scantables" % len(lst)
    # need special formatting her for history...
    from asap._asap import stmath
    stm = stmath()
    for s in lst:
        if not isinstance(s,scantable):
            msg = "Please give a list of scantables"
            if rcParams['verbose']:
                print msg
                return
            else:
                raise TypeError(msg)
    s = scantable(stm._merge(lst))
    s._add_history("merge", varlist)
    print_log()
    return s